Adsorption of lead and copper ions from aqueous solutions using multi-wall carbon nanotube/kaolinite composite beads

Abstract

In this study, adsorption of lead (Pb) and copper (Cu) ions from aqueous solution by kaolinite clay composite beads was investigated in batch systems. Alginate (crosslinker), kaolin and Multiwall carbon nanotube (MCNT) were used in the preparation of the composite beads. The composite beads were characterized using the following techniques, SEM, TGA and XRD. The adsorption parameters such as pH, metal concentration, adsorbent dose and shaking time were also studied. The Langmuir and Freundlich isotherm models were applied to describe the adsorption equilibrium process. The Langmuir model fitted well with experimental data based on correlation coefficients with maximum adsorption capacity (qmax) of 83.33 mg/g and 76.92 mg/g for lead and copper ions, respectively. It was observed that the equilibrium time for both metal ions were attained in 60 minutes. Reusability studies revealed that the composite beads maintained good adsorption capacity after being used repeatedly. The composite beads could be used in the treatment of metal-bearing effluents.

Keywords: Kaolin, alginate, carbon nanotube, beads, effluents